18438643 has 8 divisors (see below), whose sum is σ = 19038096. Its totient is φ = 17846400.

The previous prime is 18438619. The next prime is 18438649. The reversal of 18438643 is 34683481.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18438643 - 2¹⁷ = 18307571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18438649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3655 + ... + 7087.

It is an arithmetic number, because the mean of its divisors is an integer number (2379762).

Almost surely, 2^18438643 is an apocalyptic number.

18438643 is a deficient number, since it is larger than the sum of its proper divisors (599453).

18438643 is a wasteful number, since it uses less digits than its factorization.

18438643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3605.

The product of its digits is 55296, while the sum is 37.

The square root of 18438643 is about 4294.0241033324. The cubic root of 18438643 is about 264.1859103342.

The spelling of 18438643 in words is "eighteen million, four hundred thirty-eight thousand, six hundred forty-three".